Protective device for electrical circuits.



UNITED STATES PATENT OFFICE.

GIEABD B. BOSENBLATT, 0F BUTTE, MONTANA, ASSIGNOR TO WESTINGHOUSE ELEC- TRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

Specification of Letters Patent.

Patented Aug. 8, 1911.

Application filed April 4, 1906. Serial N0..309,907..

T 0 all whom it may concern:

Be it known that I, GInAno B. Rosan- BLATT, a citizen of the United States, and a resident of Butte, in the county of Silver Bow and State of Montana, have invented anew and useful Improvement in Protective Devices for Electrical Circuits, of which the following is a specification.

-My invention relates to protective devices for electrical circuits, and particularly to such devices as are adapted to operate when the currents that traverse the protected circuits exceed predetermined amounts.

The object of my invention is to provide novel and improved means of the character indicated.

For the protection of high potential circuits, it has been proposed to employ a device that is immersed inan insulating fluid, such as oil, and comprises a fusible corrductor and an inclosing tube which is ruptured, by the fusing of the conductor, to permit the oil to extinguish the arc between the fuse terminals.

My present invention, which is an improvement upon the protective means just mentioned, comprises circuit terminals that support the fuse device and means that cause said terminals to separate widely, when the inclosing tube is ruptured, for the purpose of attenuating the arc and aiding in its extinguishment.

The single figure of the accompanying drawing is a view, partially ll'l'SGClllOl'l and partially in side elevation, of a device that embodies my invention.

Supported by and between a pair of terminal aws 1 and 2, within a suitable inclosing casing 3 that is filled with an insulating fluid 4, such as oil, is a fuse device 5 that comprises terminal pieces 6 and 7 a fusible conductor 8 that is connected to and supported between the terminals 6 and 7 and an inclosing tube 9 of glass or other suitable material that may be readily ruptured upon fusing of the conductor 8. The conductor 8 is also preferably supported upon an insulating strip 10, such as mica, in order to prevent sagging thereof into engagement with the inclosing tube-when heated to any degree less than that which will cause it to fuse. The terminals 6 and 7 are provided with hooked extensions 11 and 12, respectively, that are adapted to be placed in the terminal jaws 1 and 2 and that engage corresponding shoulders 13 and 14, respectively, therein. The terminal jaw '1 may be secured to one wall of the receptacle 3 by means of a bolt 15 that may be provided, at its outer end, with an extra nut- 16 whereby a circuit conductor may be connected thereto. The terminal jaw 2 is located at the outer end of an arm 17 that is pivoted to the head of a bolt 18 which may be provided, at its .outer end, with an extra nut 19 whereby connection may be made to an external circuit. A spring 20 is provided for the purpose of normally placing the fuse device under tension, so that, when the tube 9 is ruptured, the terminals 6 and 7 may be widely separated.

It will be readily understood that, in operation, the conductor 8 fuses and breaks the inclosing tube 9 when more than a predetermined amount of current traverses it, whereby the spring 20 is permitted to effect separation of the terminals 6 and 7 and the oil is admitted to the space that was formerlyinclosed by the tube, any are that might continue to exist after fusing of the conductor being extinguished by its attenuation and by the oil.

The frangible casing for the fusible conductor is an important feature of the combination which is hereinbefore set forth for the reason that it prevents contact between the conductor and the body of liquid in which the device is immersed, and, for the further reason, that it relieves the conductor from mechanical strain, and, therefore, insures operation of the device only under certain definite limiting electrical conditions.

\Vhile I have shown a specific means whereby my invention may be put into practice, the invention, of course, is not restricted to such specific embodiment.

I claim as my invention:

1. The combination with a pair of circuit terminal members one of which is movable and each of which is provided with a notch or shoulder, of a fusible conductor having terminal pieces of hook shape to engage the notches or shoulders of said circuit terminal members, and means for effecting a wider separation of the circuit terminals when the casing is ruptured.

2. The combination ders, of a fusible cond with a pair of circuit terminal members having notches or shouluctor having terminal pieces provided with hooks that detachably 5 engage said notches or 3. The combination able circuit terminal .members notches or shoulders, to efi'ect a wider sep 0 fusible conductor ha shoulders.

with relatively movhaving and a spring tending aration thereof, of a ving terminal. pieces GIRARD B. ROSENBLATT.

Witnesses:

R. L. STEPHENS,

JNO. J. COLEMAN. 

